Avian Flu Diary: WHO WPRO Reports 2 Recent H9N2 Cases From Chinese Mainland

#19,318

While case reports remain widely scattered, and there are no signs of human-to-human spread, Mainland China's summer uptick of H9N2 continues, with 2 more cases reported over the past 2 weeks.

This follows 3 cases in June and 5 in July (see chart below), which I reported on 2 weeks ago.

Last week, the WHO WPRO Avian Influenza Weekly Update # 1058: 21 August 2026 reported:

Human infection with avian influenza A(H9N2) virus
From 14 to 20 August 2026, one new case of human infection with avian influenza A(H9N2) virus was reported to WHO in the Western Pacific Region. The case is a male child under 5 years of age from Anhui Province, China, with symptom onset on 3 August 2026. The case was hospitalised and subsequently discharged. The case had exposure to live poultry market, and no additional cases were reported from close contacts.
Since 2015, a total of 179 cases of human infection with avian influenza A(H9N2), including two deaths(both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these, 176 were reported from China, two were from Cambodia, and one was from Viet Nam.

This week, in Avian Influenza Weekly Update # 1059: 28 August 2026 they report:

Human infection with avian influenza A(H9N2) virus
From 21 to 27 August 2026, one new case of human infection with avian influenza A(H9N2) virus was reported to WHO in the Western Pacific Region. The case is a pediatric patient from Beijing Province, China,with symptom onset on 15 August 2026. The case has since recovered. The case had exposure to live poultry market, and no additional cases were reported from close contacts.
Since 2015, a total of 179 cases of human infection with avian influenza A(H9N2), including two deaths (both with underlying conditions), have been reported to WHO in the Western Pacific Region. Of these,176 were reported from China, two were from Cambodia, and one was from Viet Nam.

I'm not sure why the case counts are not being incremented, but I assume it is just an oversight. Given the limits of surveillance and testing, these reported cases are assumed to represent a subset of the actual number of spillovers into humans.

Notably, both cases reportedly had exposure at a live poultry market, which has long been recognised as a risk factor.

While H9N2 is rarely thought of as being in the same league as H5N1, the CDC lists two lineages (A(H9N2) G1 and A(H9N2) Y280) as having at least some pandemic potential, and several candidate vaccines have been developed.